The article is saying the LOC is higher for on-orbit than during launch landing. That seems counter intuitive to me. The huge ISS has been up there for nearly 19 years without taking any major hits for debris. Historically, LOC has occurred during launch and entry.
*snip*But you don't hear ASAP complaining over the lack of MMOD protection of Soyuz. Simply because there currently is no alternative to Soyuz. *snip*
All this had wringing would magically go away if Orion/SLS was the only US system of choice available to fly to ISS...
Quote from: Rocket Science on 08/24/2017 12:33 pmAll this had wringing would magically go away if Orion/SLS was the only US system of choice available to fly to ISS...Yes it would be interesting to know just how much better (?) Orion is in this regard, given all the TLC NASA has lavished on the design over so many many years. I tend to view any person, or group, by what goals they say are important to them, and then by what activities they prioritize to reach those goals. ASAP is saying this is the #1 hazard for crew transport vehicles in LEO. What is NASA doing to clean up what's already there? That's what causing this. Slowing down (or stopping) making more is good, but how can you sweep a large volume of near Earth space cheaply of the very large number of objects too small for radar (IIRC everything < 5cm is invisible to ground radar) but still big enough to do damage?If "Aerospace Safety" is their key task (which it is) shouldn't that be a key long term investigation for them?
Quote from: woods170 on 08/24/2017 06:04 am*snip*But you don't hear ASAP complaining over the lack of MMOD protection of Soyuz. Simply because there currently is no alternative to Soyuz. *snip*The Soyuz are covered with layers of thermal insulation with an outer MMOD protection layer.
Quote from: whitelancer64 on 08/24/2017 02:22 pmQuote from: woods170 on 08/24/2017 06:04 am*snip*But you don't hear ASAP complaining over the lack of MMOD protection of Soyuz. Simply because there currently is no alternative to Soyuz. *snip*The Soyuz are covered with layers of thermal insulation with an outer MMOD protection layer. Yes, and the "stopping power" of that set-up on Soyuz is considerably less than that of the CCP ships and almost non-existent compared to the set-up used on the USOS modules of ISS.
From the article, and just so we more directly discuss/debate the issues:QuoteThe ASAP was presented with the three main “programmatic and safety risks” currently challenging the CCP, noted as the:A. “inability to meet Loss of Crew (LOC) metricsB. DoD’s Search and Rescue posture and capabilityC. the possibility of aborts taking place in sea states that would be unsafe for rescue.”It would seem to me that "B & C" might be easier to quantify and address, although both are contingent on weather and sea conditions that could change from moment to moment, which would be unpredictable.
The ASAP was presented with the three main “programmatic and safety risks” currently challenging the CCP, noted as the:A. “inability to meet Loss of Crew (LOC) metricsB. DoD’s Search and Rescue posture and capabilityC. the possibility of aborts taking place in sea states that would be unsafe for rescue.”
>At this point it is better for ASAP to ensure the companies have not missed anything. No oxygen tanks that will short out and explode.
IMO, using solar power rather than fuel cells is a big safety step. Hopefully Kilopower will prove itself useful and up the ante for BEO.
Quote from: docmordrid on 08/25/2017 08:46 amIMO, using solar power rather than fuel cells is a big safety step. Hopefully Kilopower will prove itself useful and up the ante for BEO.Kilopower is still a ways from first ground test. I think it's got excellent prospects for use on future probes but its now the baseline for the Mars DRA because NASA already had a 40Kw nuclear reactor as one of their options.I think it's a huge leap to consider it for human crewed BEO anytime soon.
Kilopower should be available when a Moon base or Moon vehicle needs power. A robotic Moon base away from the poles is likely to need power. This will allow ASAP to measure the reliability in a working environment.
Quote from: woods170 on 08/24/2017 05:18 pmQuote from: whitelancer64 on 08/24/2017 02:22 pmQuote from: woods170 on 08/24/2017 06:04 am*snip*But you don't hear ASAP complaining over the lack of MMOD protection of Soyuz. Simply because there currently is no alternative to Soyuz. *snip*The Soyuz are covered with layers of thermal insulation with an outer MMOD protection layer. Yes, and the "stopping power" of that set-up on Soyuz is considerably less than that of the CCP ships and almost non-existent compared to the set-up used on the USOS modules of ISS.If you say so.
woods170 is correct on this. It's better than it was -- it got upgraded from "terrifying" to "not all that great."
Quote from: SWGlassPit on 09/01/2017 06:26 pmwoods170 is correct on this. It's better than it was -- it got upgraded from "terrifying" to "not all that great."Gravity has taught us that Soyuz can be bombarded with orbital debris and still survive reentry.
That was a Shenzhou. Wonder if anyone in the west looked at Shenzhou's LOC risks..
Quote from: RonM on 09/04/2017 03:48 pmThat was a Shenzhou. Wonder if anyone in the west looked at Shenzhou's LOC risks..I'm gonna guess they are ahead of Soyuz simply by the virtue of not landing in Siberia and needing a TP-82 for protection from local fauna.
I dunno about that. IIRC, there was a report on Shuttle risks that identified the one-shot, high-speed landing as one of the larger risks. One flight touched down short of the runway.